The disclosed embodiments herein relate to a method performed by a UE; a UE, a method performed by a location server and a location server and computer programs respectively. The method performed by the UE comprises: receiving from a location server NetWork assisted Reference Signal Time Difference, RSTD, Quantization Information, NW-QI; performing RSTD measurements by measuring or estimating a Time Of Arrival, TOA, of a Positioning Reference Signal, PRS, from respective base station of a plurality of base stations; encoding the RSTD measurements by employing a Enhanced RSTD Quantization Method, E-QM, or by using the NW-QI while encoding the RSTD measurements; and sending UE assisted RSTD Quantization Information, UE-QI, to the location server, the UE-QI including the encoded RSTD measurements.